Patent document DE 10 2005 057 267 A1 discusses a method for detecting the condition of the driver, in which a reduced attentional state of the driver is inferred from the subsequent steering angle correction process in the event of a lane departure. The departure from the original lane is ascertained from data of a lane keeping system, the steering angle correction process from the measured signals of a steering angle sensor, which are compared with a typical reaction pattern. Reduced attention may usually be assumed when there is a sudden steering angle change in response to the departure from the lane after a phase of little activity.